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One Sprinkler Head in Zone Does Not Operate

Hi All,

I have a 9-zone sprinkler system with each zone having approximately 4 to 6 sprinklers. On one zone, all sprinkler heads perform as designed except the last one (at least it appears to be the last sprinkler attached to the zone) is getting nominal water pressure and the head is not popping up.

All other heads in the zone functional perfect. I've done some research to learn that perhaps the flow control valve for this zone may be partially open, causing the one head to not get sufficient water pressure. I've replaced the non-working head and the problem continues. Could there be blockage in the line preventing sufficient water from getting to that last head or should I direct focus to the flow control valve for this zone? If so, where would I locate the flow control valve for each zone?

If I'm completely off base here, what might other troubleshooting options be? Many thanks!

RE: One Sprinkler Head in Zone Does Not Operate

On one zone, all sprinkler heads perform as designed except the last one (at least it appears to be the last sprinkler attached to the zone) is getting nominal water pressure and the head is not popping up.

All other heads in the zone functional perfect. I've done some research to learn that perhaps the flow control valve for this zone may be partially open, causing the one head to not get sufficient water pressure. I've replaced the non-working head and the problem continues. Could there be blockage in the line preventing sufficient water from getting to that last head or should I direct focus to the flow control valve for this zone? If so, where would I locate the flow control valve for each zone?

Normally the feed line to an irrigation zone should enter the zone at or close to the mid-point to give all heads even pressure. If the feed line is at one end of the zone pipe, the first head will ge the most pressure, then the second one will get a little less pressure, and so on.

Yes, there could be an obstruction in the pipe, or the pipe itself could be too small.

You also haven't told us what kind of heads that they are; gear drives, spray heads, MP Rotators? We don't know what your working pressure is, your flow rates, or your pipe type or diameter.

I would start at opening the flow control to the maximum, and taking a pressure reading on each head to see what you are working with. If the pressure drops dramaticly from the second to last head to the last head, then there is probably something in the line that shouldn't be there. You might also want to take the last head and the swing joint off and flush the line just to make sure.